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Abstract  We have studied the interaction of benzonitrile with as-prepared and purified single-walled carbon nanotubes (SWCNTs). As-prepared SWCNTs, when suspended in benzonitrile, lead to a red colored dispersion which contains fragments composed mostly of amorphous carbon and carbon-coated catalyst, thus suggesting that benzonitrile is a solvent that can be used as one step of the purification process. Optical spectroscopic data (infrared, Raman, absorption) showed that purified carbon nanotubes interact weakly with benzonitrile. These experimental results are confirmed by first principles calculations that predict a very weak adsorption process through π–π interaction instead of through the free electron pair of the nitrile. [ABSTRACT FROM AUTHOR]

The physicochemical modeling of the behavior of impurities in the course of their preconcentration by the chemical distillation of the sample matrix consisting of granules of a solid solution of impurities in bismuth oxide was carried out. It was supposed that the distillation process is conducted in a kinetic mode. The results of calculations by the model are compared with the earlier results of modeling of the behavior of impurities in distilling a heterophase sample consisting of matrix (bismuth oxide) granules and granules of impurity oxides. The experimental data and results of calculations by the model agree well. [ABSTRACT FROM AUTHOR]

This paper discusses basic distinctions and challenges of available commercial process technologies for fractionation of phenol and acetone products, and for removal of contaminants therefrom. Theoretical improbability of complete removal of impurities from the desired products under fractionation process conditions is conclusively demonstrated. The challenge of achieving an adequate quality of desired products (i.e., of phenol, acetone, and α-methylstyrene) has been effectively met within the framework of state-of-the-art phenol/acetone production process. [ABSTRACT FROM AUTHOR]

This paper presents structural relationships of phase equilibrium diagrams and azeotropic properties, and resulting evaluation of optimum process conditions for removal of hydroxyacetone (HA) and 2-methylbenzofuran (2-MBF) from phenol. It is demonstrated that the concentration region of HA separation from phenol is absolutely different from that for 2-MBF, which makes the task of HA and 2-MBF removal from phenol by distillation requiring installation of at least two highly selective extractive distillation columns operating with significant steam consumption. [ABSTRACT FROM AUTHOR]

Abstract  Regularities of adsorption by clay of some commercial sorts of anthocyans extracted from plant materials are investigated. The interrelation between sorption ability and structure of sorbates is revealed. Introduction of organic solvent is shown providing a possibility of targeted changing sorption properties of system and sorption purification of anthocyans. [ABSTRACT FROM AUTHOR]

Abstract  Xylanases produced from a locally isolated strain of Thermomyces lanuginosus and its mutant derivative were purified to a yield of 39.1 and 42.83% with specific activities of 15,501 and 17,778 IU mg−1 protein, respectively. The purification consisted of two steps i.e., ammonium sulphate precipitation, and gel filtration chromatography. The mutant enzyme showed high affinity for substrate, with a K m of 0.098 mg ml−1 as compared to wild type enzyme showing K m of not less than 0.112 mg ml−1. It was found that pH values of 8.1 and 7.3 were best for activity of the mutant and wild-type-derived enzymes, respectively. The values of pK a of the acidic limbs of both enzymes were the same (5.0 and 4.9, respectively) but the pK a value of the basic limb was slightly increased, indicating the participation of a carboxyl group present in a non-polar environment. Temperatures of 70 and 65°C were found optimal for mutant and wild-derived xylanase, respectively. Enzymes displayed a high thermostability showing a half life of 31.79 and 6.0 min (5.3-fold improvement), enthalpy of denaturation (ΔH*) of 146.06 and 166.95 kJ mol−1, entropy of denaturation (ΔS*) of 101.44 and 174.67, and free energy of denaturation (ΔG*) of 110.25 and 105.29 kJ mol−1 for mutant- and wild-organism derived enzyme, respectively at 80°C. Studies on the folding and stability of cellulase-less xylanases are important, since their biotechnological employments require them to function under extreme conditions of pH and temperature. The kinetic and thermodynamic properties suggested that the xylanase from the mutant organism is better as compared to xylanase produced from the wild type and previously reported strains of same species, and may have a potential usage in various industrial fields. [ABSTRACT FROM AUTHOR]

Abstract  A facile and fast approach for the purification of deoxycytidine kinase (dCK) from calf thymus was developed using a fast performance liquid chromatography system. A 73-fold enrichment of the enzyme was noted compared to unfractionated dCK. Characterization studies demonstrated that dCK had a molecular mass of 31 kDa using SDS–PAGE, an optimum pH of 7.0 and the enzyme maintained stability between 30 and 40°C. The rapid preparation of dCK demonstrated here will be valuable in the synthesis of nucleotide analogs. [ABSTRACT FROM AUTHOR]

Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) was produced by Saccharomyces cerevisiae. A two-stage cultivation strategy with mixture of glucose and galactose was developed to enhance rhPDGF-BB production, with its concentration being 32 mg/l fermentation broth under optimal conditions: corn steep powder as nitrogen source, 2 g/1 of glucose concentration at the beginning of induction phase, a pH of 5.0 and 6.5 for cell growth and rhPDGF-BB accumulation. The purification process consisted of yeast supernatant ultrafiltration followed by ion exchange chromatography and molecular sieve, and the recovery of rhPDGF-BB was estimated to be 20.28%. Biological activity of the purified rhPDGF-BB was 3.05 ng/ml. [ABSTRACT FROM AUTHOR]

Eight new acidochromic dyes have been synthesised that can be used for optically monitoring pH in the range from 3 to 12. Their corresponding p K a values have been both measured and calculated theoretically by means of density functional theory. The synthesis of these new dyes is facile without the need for chromatographic purification. The dyes can be covalently linked to polymers containing hydroxyl functions such as cellulose, polyurethane hydrogel, and hydroxyalkyl methacrylate. The resulting sensor layers exhibit significant colour changes both in the UV and in the visible spectral range. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Characterization of humic substances (HS) in environmental samples generally involves labor-intensive and time-consuming isolation and purification procedures. In this paper, the development of an automated system for HS isolation and purification is described. The novelty of the developed system lies in the way the multiple liquids and columns used in the isolation/purification procedure are handled in both forward and back-elution mode by solenoid valves. The automated procedure significantly reduces the total throughput time needed, from 6–7 days to 48 h, and the amount of labor to obtain purified HS for further characterization. Chemical characterization of purified HS showed that results were in good agreement with previously published values for HS from a variety of sources, including the IHSS standard HS collection. It was also shown that the general properties of HS were consistent among the different source materials (soil, waste, aquatic) used in this study. The developed system greatly facilitates isolation and characterization of HS and reduces the risk of potential (time-dependent) alteration of HS properties in the manual procedure. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract  Composition and characteristics of lignosulfonic acids recovered from technical-grade ligno-sufonates were studied by IR spectroscopy, viscometry, and elemental and chemical analyses. The dependence of the chemical composition and characteristics of lignosulfonic acids on the procedures of their recovery and purification was examined. [ABSTRACT FROM AUTHOR]

Using computer simulation, we have studied the effects of principal process parameters on the yield of a substance being purified to the desired purity level in a middle-vessel packed batch distillation column, with examples for isotopically pure silane. The results indicate that there are the optimal column height, reflux rate, and charge weight, which minimize the loss of the substance being purified. [ABSTRACT FROM AUTHOR]

Abstract  In the present study a method to detect and identify the integration site of a foreign DNA sequence, e.g., a horizontally transferred DNA sequence is described. For this purpose a model was developed to simulate a tissue sample. The method includes four main steps; (a) digestion of DNA, (b) ligation of adaptors to the digestion sites, (c) solid phase purification and (d) PCR amplification. Solid phase purification of the amplified targets markedly improved the sensitivity of the method and the described method was found to be able to detect approximately two copies of a target sequence in a DNA background of 25 ng, corresponding to a single integration site in a single dividing cell in a tissue sample. The model consists of salmon and soy DNA, where the soy DNA simulates DNA from feed taken up from the gastrointestinal tract of salmon. [ABSTRACT FROM AUTHOR]

Abstract  A superoxide dismutase (SOD) was purified from Spirulina platensis sonicate. The SOD was purified to homogeneity (48-fold and 0.24% yield) through ammonium sulphate precipitation and DEAE-52 anion exchange chromatography. The SOD from S. platensis appeared to be a homodimer with a molecular weight of 30 kDa and a subunit MW of 15 kDa as determined by both native polyacrylamide gel electrophoresis and mass spectrometry. The enzyme activity was stable at pH 6.5–10.0 and 50 �C. Using group-specific chemical modifying reagents, the amino acids arginine, histidine, tryptophan, tyrosine and aspartic acid were identified to be essential for S. platensis SOD activity. The amino acid composition was found to lack methionine and cysteine. The inhibition of activity by H2O2 suggests that the enzyme may be an iron containing SOD. [ABSTRACT FROM AUTHOR]

Purification methods for proteomics samples are of crucial concern for improving the quality of the sample delivered to the mass spectrometer. They constitute the link between the mass spectrometer and protein processing and peptide isolation steps that usually require solvents, buffers, or detergents completely incompatible with MS-analysis conditions. This work describes three new clean-up procedures using synthetic membranes and polymer media and compares them with standard procedures. The efficiency of each of the purification procedures was studied via application to four standards and two membrane proteins. This work highlights the importance of versatility in sample preparation, especially for MS-based proteomic investigations. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Growth on a wheat bran media induced production of an extracellular β-glucanase by Rhizomucor miehei (DSM 1330). The enzyme was purified to homogeneity. Substrate specificity studies coupled with protein database similarity searching using mass spectrometry-derived sequence data indicate it to be an endo-1,3(4)-β-glucanase (EC 3.2.1.6). The enzyme was characterised in terms of potential suitability for use in animal (poultry) feed. Significant activity was observed over the entire pH range typical of the avian upper digestive tract (pH 2.6–6.5). The enzyme was also found to be more thermostable than current commercialized β-glucanases, particularly when heated at a high enzyme concentration, and retained twice as much residual activity as the latter upon exposure to simulated avian digestive tract conditions. There are no previous reports of the production, purification or characterization of a β-glucanase from a Rhizomucor, and the enzyme’s application-relevant physicochemical characteristics render it potentially suited for use in animal feed. [ABSTRACT FROM AUTHOR]

The accumulation dynamics of cellulolytic enzymes in culture media of the basidiomycete fungi Panus tigrinus, Pleurotus ostreatus, Fomes fomentarus, and the micromycete Aspergillus terreus were studied during a long incubation period. It was found that A. terreus was the most active producer of cellulolytic enzymes among the studied fungi. Two protein fractions with cellulase activity were isolated using gel filtration and ion-exchange chromatography. PAAG electrophoresis showed that fraction-I consisted of four components; fraction-II, an electrophoretically homogeneous protein. [ABSTRACT FROM AUTHOR]

An improved method for the preparation and purification of ethyl 2-hydroxy-4-oxo-4H-pyrido[1,2-a]-pyrimidine-3-carboxylates is proposed. According to 1H and 13C NMR spectroscopic data the synthesized compounds exist in DMSO solution in the 2-hydroxy-4-oxo form while in the crystal (at least for the case of the unsubstituted derivative) X-ray analysis shows that it occurs in the bipolar 2,4-dioxo form. [ABSTRACT FROM AUTHOR]

In order to search for isotopic anomalies of U caused by the disintegration of 247Cm in meteorite samples, an analytical scheme for determining 235U/238U ratio for a small amount of uranium (less than 1 ng U) was established. The isotopic ratio of U was determined by double-focusing inductively coupled plasma mass spectrometry (DF-ICP-MS). With a great improvement of chemical procedure for purifying the uranium fraction separated from meteorite samples, a variation in 235U/238U ratios was resolved at an order of ±4‰ for 100 ppt or 200 pg U in solution. For applying the procedure in searching an evidence of 247Cm as an extinct radionuclide in the early solar system, a selective chemical dissolution of constituent minerals of meteorites using EDTA and HCl was introduced and a chemical purification scheme of uranium for ICP-MS was established. [ABSTRACT FROM AUTHOR]

Three hundred and thirty two bacterial colonies were isolated from soil contaminated by an oil spill. All the bacteria were cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used ( n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation (AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the carrier. From the retention data, the hydrodynamic diameter ( d H) and molecular weight ( M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration standards. The d H and M were 49 nm and 2.3 × 105 Da when extracted with n-hexane, and 39 nm and 1.13 × 105 Da when extracted with the 2:1 mixture of chloroform/MeOH, respectively. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Tandem affinity purification (TAP) is a generic two-step affinity purification protocol that enables the isolation of protein complexes under close-to-physiological conditions for subsequent analysis by mass spectrometry. Although TAP was instrumental in elucidating the yeast cellular machinery, in mammalian cells the method suffers from a low overall yield. We designed several dual-affinity tags optimized for use in mammalian cells and compared the efficiency of each tag to the conventional TAP tag. A tag based on protein G and the streptavidin-binding peptide (GS-TAP) resulted in a tenfold increase in protein-complex yield and improved the specificity of the procedure. This allows purification of protein complexes that were hitherto not amenable to TAP and use of less starting material, leading to higher success rates and enabling systematic interaction proteomics projects. Using the well-characterized Ku70-Ku80 protein complex as an example, we identified both core elements as well as new candidate effectors.*Note: In the version of this article initially published online, the GS-TAP tag in Figure 3b was incorrectly identified as a GC-TAP tag, and the email address for material requests (materials@cemm.oeaw.ac.at) was omitted from the methods section. The errors have been corrected for all versions of the article. [ABSTRACT FROM AUTHOR]

Aspergillus niger K10 cultivated on 2-cyanopyridine produced high levels of an intracellular nitrilase, which was partially purified {18.6-fold) with a 24% yield. The N-terminal amino acid sequence of the enzyme was highly homologous with that of a putative nitrilase from Aspergillus fumigatus Af293. The enzyme was copurified with two proteins, the N-terminal amino acid sequences of which revealed high homology with those of hsp60 and an ubiquitin-conjugating enzyme. The nitrilase exhibited maximum activity (91.6 U mg"1) at 45°C and pH 8.O. Its preferred substrates, in the descending order, were 4-cyanopyridine, benzonitrile, 1,4-dicyanobenzene, thio- phen-2-acetonitrile, 3-chlorobenzonitrile, 3-cyanopyridine, and 4-chlorobenzonitrile. Formation of amides as byproducts was most intensive, in the descending order, for 2-cyanopyridine, 4-chlorobenzonitrile, 4-cyanopyridine, and 1,4-dicyanobenzene. The enzyme stability was markedly improved in the presence of D-sorbitol or xylitol (20% wfv each). p-Hydroxymercuribenzoate and heavy metal ions were the most powerful inhibitors of the enzyme. [ABSTRACT FROM AUTHOR]

Nucleic acid separation is an increasingly important tool for molecular biology. Before modern technologies could be used, nucleic acid separation had been a time- and work-consuming process based on several extraction and centrifugation steps, often limited by small yields and low purities of the separation products, and not suited for automation and up-scaling. During the last few years, specifically functionalised magnetic particles were developed. Together with an appropriate buffer system, they allow for the quick and efficient purification directly after their extraction from crude cell extracts. Centrifugation steps were avoided. In addition, the new approach provided for an easy automation of the entire process and the isolation of nucleic acids from larger sample volumes. This review describes traditional methods and methods based on magnetic particles for nucleic acid purification. The synthesis of a variety of magnetic particles is presented in more detail. Various suppliers of magnetic particles for nucleic acid separation as well as suppliers offering particle-based kits for a variety of different sample materials are listed. Furthermore, commercially available manual magnetic separators and automated systems for magnetic particle handling and liquid handling are mentioned. [ABSTRACT FROM AUTHOR]

The article provides information on the chemical experiments on the physiochemical aspects of tungsten powder production. The process which involves seperation of tungsten oxide and other compounds by purifying and reducing. The experiment investigates the condition of tungsten powder production by reducing tungsten oxides in melts of alkali metal carbonates. The article describes the process followed and the results achieved.

l-2-Amino-Δ2-thiazoline-4-carboxylic acid hydrolase (ATC hydrolase) was purified and characterized from the crude extract of Escherichia coli, in which the gene for ATC hydrolase of Pseudomonas sp. strain ON-4a was expressed. The results of SDS–polyacrylamide gel electrophoresis and gel filtration on Sephacryl S-200 suggested that the ATC hydrolase was a tetrameric enzyme consisted of identical 25-kDa subunits. The optimum pH and temperature of the enzyme activity were pH 7.0 and 30–35°C, respectively. The enzyme did not require divalent cations for the expression of the activity, and Cu2+ and Mn2+ ions strongly inhibited the enzyme activity. An inhibition experiment by diethylpyrocarbonic acid, 2-hydroxy-5-nitrobenzyl bromide, and N-bromosuccinimide suggested that tryptophan, cysteine, or/and histidine residues may be involved in the catalytic site of this enzyme. The enzyme was strictly specific for the l-form of d, l-ATC and exhibited high activity for the hydrolysis of l-ATC with the values of K m (0.35 mM) and V max (69.0 U/mg protein). This enzyme could not cleave the ring structure of derivatives of thiazole, thiazoline, and thiazolidine tested, except for d, l- and l-ATC. These results show that the ATC hydrolase is a novel enzyme cleaving the carbon–sulfur bond in a ring structure of l-ATC to produce N-carbamoyl- l-cysteine. [ABSTRACT FROM AUTHOR]

An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods. [ABSTRACT FROM AUTHOR]

Dense boron samples with a glassy structure have been prepared for the first time by high-pressure sintering of amorphous boron powder at temperatures from 750 to 1100 K. Analysis of the mechanical properties of boron samples sintered at pressures from 2 to 8 GPa and different temperatures indicates that sintering proceeds most effectively near 750 K. Purification of amorphous boron in water is shown to be effective in removing products of boron oxidation in air. [ABSTRACT FROM AUTHOR]

We overexpressed duplex-specific nuclease (DSN) from Kamchatka crab in Escherichia coli cells and developed procedures for purification, renaturation, and activation of this protein. We demonstrated identity of the properties of the native and recombinant DSN. We also successfully applied the recombinant DSN for full-length cDNA library normalization. [ABSTRACT FROM AUTHOR]

We purified cathepsins B1 and B2 from the ordinary muscle of carp Cyprinus carpio. The N-terminal amino acid sequences (12 residues) of 29 kDa bands of cathepsins B1 and B2 are the same and showed high homology of 75% and 83%, respectively, with the heavy chain of rat and human cathepsins B. Based on conserved sequences of other cathepsins B and the N-terminal amino acid sequences of 29 kDa bands, we cloned carp cathepsin B cDNA. The nucleotide sequence of carp cathepsin B cDNA consists of 1470 bp including a 993 bp open reading frame, encoding a deduced protein of 330 amino acids. The deduced amino acid sequence of carp cathepsin B has similarity of 80% to rainbow trout cathepsin B and of 76–78% to other vertebrate cathepsins B. The sequence of its isoform was also determined during molecular cloning, which has 94.8% similarity with first cloned cathepsin B. They are completely same in N-terminal amino acid sequence of heavy chain, active site and potential N-glycosylation site. This indicates there are at least two kinds of cathepsin B functioning in vivo in carp. [ABSTRACT FROM AUTHOR]

The Wendler version of the Torgov-Ananchenko scheme of total steroid synthesis was shown to be applicable to the preparation of 6-oxaestra-1,3,5(10),8,14-pentaenes. Conditions for cyclodehydration of secosteroids thus obtained were found, which ensured isolation of the target compounds in a high yield without using chromatographic purification methods. [ABSTRACT FROM AUTHOR]

A purification scheme involving ion exchange chromatography on diethylaminoethyl (DEAE) cellulose, carboxymethyl (CM) cellulose, and Q-Sepharose, followed by fast protein liquid chromatography–gel filtration on Superdex 75, was utilized to isolate a laccase from the fruiting bodies of the mushroom Pleurotus eryngii. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose and unadsorbed on CM-cellulose. The molecular mass of the laccase in sodium dodecyl sulfate–polyacrylamide gel electrophoresis was 34 kDa. The laccase activity was maximal at 70°C and remained high at 80°C. High activity of the laccase was maintained at ph 3 to 5. The activity underwent an abrupt decline at pH 6 and 7 and was indiscernible at ph 8 and 9. The laccase exhibited an inhibitory activity toward HIV-1 reverse transcriptase with an IC50 of 2.2 μM. Its N-terminal sequence was dissimilar to those of laccase isoenzymes previously isolated from cultured mycelia of the same species. [ABSTRACT FROM AUTHOR]

The increasing demands for indium in recent years require high purity indium as raw materials. Physical-chemical purification and electrorefining have been performed to obtain 6N high purity indium. Indium is smelted by using NaOH, NaCl and NaNO3 for 20 min at 400°C, the removing rate of Sn, Zn, Al reaches 40, 60 and 37% respectively. The removing rate of Cd is 90–95% and that of Tl reaches 40–60% when indium is smelted for 10 min by 20% glycerin solution of KI and I2 at 180°C. When indium metal is vacuum refined in two stages: 800–900°C for 2 h and 950–1050°C for 2 h, the major impurity elements, Pb, Zn, and Bi, are effectively removed. When indium is electrolytic refined in In2(SO4)3-H2SO4 system, in which indium content is 60–80 g/L, pH 2.0–3.0, current density 50–80 A/m2, the content of impurities can be dropped and the product of indium reaches 99.9999%. [ABSTRACT FROM AUTHOR]

The highly enantioselective arylacetonitrilase of Pseudomonas putida was purified to homogeneity using a combination of (NH4)2SO4 fractionation and different chromatographic techniques. The enzyme has a molecular weight of 412 kDa and consisted of approximately nine to ten identical subunits (43 kDa). The purified enzyme exhibited a pH optimum of 7.0 and temperature optimum of 40°C. The nitrilase was highly susceptible to thiol-specific reagents and metal ions and also required a reducing environment for its activity. These reflected the presence of a catalytically essential thiol group for enzyme activity which is in accordance with the proposed mechanism for nitrilase-catalyzed reaction. The enzyme was highly specific for arylacetonitriles with phenylacetonitrile and its derivatives being the most preferred substrates. Higher specificity constant ( k cat/ K m) values for phenylacetonitrile compared to mandelonitrile also revealed the same. Faster reaction rate achieved with this nitrilase for mandelonitrile hydrolysis was possibly due to the low activation energy required by the protein. Incorporation of low concentration (<5%) of organic solvent increased the enzyme activity by increasing the availability of the substrate. Higher stability of the enzyme at slightly alkaline pH and ambient temperature provides an excellent opportunity to establish a dynamic kinetic resolution process for the production of ( R)-(−)-mandelic acid from readily available mandelonitrile. [ABSTRACT FROM AUTHOR]

Pichia pastoris β-glucosidase was purified to apparent homogeneity by salting out with ammonium sulfate, gel filtration, and ion-exchange chromatography with Q-Sepharose and CM-Sepharose. The enzyme is a tetramer (275 kD) made up of four identical subunits (70 kD). The pH optimum is 7.3, and it is fairly stable in the pH range 5.5–9.5. The temperature optimum is 40°C. The purified β-glucosidase is effectively active on p-/ o-nitrophenyl-β-D-glucopyranosides ( p-/ o-NPG) and 4-methylumbelliferyl-β-D-glucopyranoside (4-MUG) with K m values of 0.12, 0.22, and 0.096 mM and V max values of 10.0, 11.7, and 6.2 µmol/min per mg protein, respectively. It also exhibits different levels of activity against p-nitrophenyl-1-thio-β-D-glucopyranoside, cellobiose, gentiobiose, amygdalin, prunasin, salicin, and linamarin. The enzyme is competitively inhibited by gluconolactone, p-/ o-nitrophenyl-β-D-fucopyranosides ( p-/ o-NPF), and glucose against p-NPG as substrate. o-NPF is the most effective inhibitor of the enzyme activity with K i value of 0.41 mM. The enzyme is more tolerant to glucose inhibition with K i value of 7.2 mM for p-NPG. Pichia pastoris has been employed as a host for the functional expression of heterologous β-glucosidases and the risk of high background β-glucosidase activity is discussed. [ABSTRACT FROM AUTHOR]

Separation and purification of133Xe from acidic solution containing uranium,99Mo and131I has been developed. In the first step of this work, uranium pellets were dissolved under pressure (8-15 bar) in 8M nitric acid solution. Then133 Xe and other gases were conducted to activated charcoal cold trap. Final purification of133Xe from impurities such as NO x, radioiodine and krypton was performed by passing through a molecular sieve preparative chromatographic column using helium as mobile phase. The final recovery of133Xe from the separation-purification process was higher than 98%. Adsorption-desorption behavior of radioxenon on the charcoal and molecular sieves have also been studied and discussed. [ABSTRACT FROM AUTHOR]

It is shown that the modular technology of high-purity hycirofluoric acid can be optimized along two lines: replacement of the module for the chemical treatment of the acid by a more efficient one and the introduction of a hydroionic convection module for reducing the concentration of ionic impurities. [ABSTRACT FROM AUTHOR]

The halophilic archaeon Haloferax mediterranei is able to grow in a minimal medium containing ammonium acetate as a carbon and nitrogen source. When this medium is enriched with starch, α-amylase activity is excreted to the medium in low concentration. Here we report methods to concentrate and purify the enzyme. The relative molecular mass of the enzyme, determined by gel filtration, is 50±4 kDa, and on SDS-PAGE analysis a single band appeared at 58 kDa. These results indicated that the halophilic α-amylase is a monomeric enzyme. The enzyme showed a salt requirement for both stability and activity, being stable from 2 to 4 M NaCl, with maximal activity at 3 M NaCl. The enzyme displayed maximal activity at pHs from 7 to 8, and its optimal temperature was in a range from 50 °C to 60 °C. The results also implicated several prototropic groups in the catalytic reaction. [ABSTRACT FROM AUTHOR]

The cytoplasmic pyrophosphatase of the photosynthetic bacterium Rhodospirillum rubrum was purified to electrophoretic homogeneity. The enzyme is a homohexamer of 20-kDa monomers. The gene was cloned and sequenced. Alignment of the deduced 179-amino-acid protein with known bacterial pyrophosphatases revealed conservation of all residues in the active site. Attempts to obtain an insertion mutant of the cytoplasmic pyrophosphatase gene did not yield any cell completely devoid of cytoplasmic pyrophosphatase activity. The mutants obtained showed 50% of the enzymatic activity and grew in twice the generation time of wild-type cells. This suggests that the membrane-bound pyrophosphatase of Rsp. rubrum is not sufficient for a normal growth rate, whereas the cytoplasmic enzyme is essential for growth. The characteristics of the gene and the encoded protein fit those of prokaryotic family I pyrophosphatases. [ABSTRACT FROM AUTHOR]

Abstract. A new purification procedure is introduced, which uses the advantages of column chromatography and vacuum filtration. Potassium polyacrylate is used as stationary phase. This method is based on the idea that the size of the existing cavities in the polymer increases during a swelling process in distilled water. The cavities am big enough to entrap the nanoparticles, but allow for a free movement of nanotubes and bundles. [ABSTRACT FROM AUTHOR]

The naturally occurring octacyclopeptide brachystemin F was synthesized for the first time in the present study by a two-step solid-phase/solution strategy. All the amino acids in this study have the L-configuration. The linear octapeptide was assembled by standard Fmoc solid-phase peptide synthesis (SPPS), and subsequent cyclization was carried out by the solution method. The target compound was purified by preparative RP-HPLC, and its structure was identified by H NMR, C NMR, and MS. [ABSTRACT FROM AUTHOR]

The article presents a phytochemical investigation on the chemical constituents of Alisma orientalis, a Alismataceae genus that is widely cultivated in China and Japan. The compounds include altaicalarin B, alisol A and arnidiol. The plant materials used in the investigation and the detailed extract, isolation, and purification process are outlined.

The goal of this study was to identify and biochemically characterize a novel hyperthermostable keratinase from microorganisms for feather waste degradation. Here, a hyperthermophilic Geoglobus acetivorans keratinase (GacK) gene was chosen based on a search of a sequence database. The selected GacK gene was synthesized, cloned, and successfully expressed without a signal peptide in the E. coli system. A monomer of approximately 58 kDa was obtained in a soluble form and purified. The recombinant GacK displayed the highest activity at an optimum temperature of 100 °C and a pH of 10. The hyperthermostable GacK enzymatic performance remained high even after incubation in nonionic surfactants and the chelating agent EDTA. The residual and keratinolytic activities of GacK, as determined with azocasein and keratin azure used as substrates, remained significantly greater than 80% at 130 °C for 7 h. The kinetic parameters Km and Vmax for azure keratin were 0.41 mg/ml and 875.14 unit/mg, respectively, while those for azocasein were 1.51 mg/ml and 505.32 unit/mg, respectively. The results suggest that the enzyme is among the most hyperthermostable keratinases. Because of its enzymatic characteristics to degrade keratin azure at high temperatures, GacK may potentially be utilized in future industrial applications. [ABSTRACT FROM AUTHOR]

Membrane protein purification is a laborious, expensive, and protracted process involving detergents for its extraction. Purifying functionally active form of membrane protein in sufficient quantity is a major bottleneck in establishing its structure and understanding the functional mechanism. Although overexpression of the membrane proteins has been achieved by recombinant DNA technology, a majority of the protein remains insoluble as inclusion bodies, which is extracted by detergents. Detergent removal is essential for retaining protein structure, function, and subsequent purification techniques. In this study, we have proposed a new approach for detergent removal from the solubilized extract of a recombinant membrane protein: human phospholipid scramblase 3 (hPLSCR3). N-lauryl sarcosine (NLS) has been established as an effective detergent to extract the functionally active recombinant 6X-his- hPLSCR3 from the inclusion bodies. NLS removal before affinity-based purification is essential as the detergent interferes with the matrix binding. Detergent removal by adsorption onto hydrophobic polystyrene beads has been methodically studied and established that the current approach was 10 times faster than the conventional dialysis method. The study established the potency of polystyrene-based beads as a convenient, efficient, and alternate tool to dialysis in detergent removal without significantly altering the structure and function of the membrane protein. [ABSTRACT FROM AUTHOR]

The article focuses on the report with regards to the catalytic reaction that transfer allyl groups into activated imines. It states that the catalytic reaction can deliver homoallylic alcohols from carbonyls, and homoallylic amine derivatives from activated imines, which can also make molecular complexity. Furthermore, it says that the use of chiral auxiliaries is common in effective allylation processes, and need substantial effort in purifying reaction mixture's desired product.

Abstract  The conditions for the sulfation of rough baddeleyite concentrate to remove impurity minerals were studied. [ABSTRACT FROM AUTHOR]

Sodium hydrogen sulfite was used to promote condensation of o-phenylenediamine with aromatic aldehydes in dimethylformamide to obtain the corresponding 2-arylbenzimidazoles. The procedure is simple and convenient, and it implies inexpensive promoter and is characterized by short reaction time and easy purification of the final products. [ABSTRACT FROM AUTHOR]

The article provides information on the study on the ixeridium gracile plant. The plant is a herbaceous perennial plant which belongs to the Compositae family and is used as a representative Tibetan herbal medicine. The study involves the isolation and purification of eleven triterpenoids compounds and three steroids from an alcoholic extract of the whole plant of ixeridium gracile.

The oxygen fugacity fO2of the Earth’s mantle is one of the fundamental variables in mantle petrology. Through ferric–ferrous iron and carbon–hydrogen–oxygen equilibria, fO2 influences the pressure–temperature positions of mantle solidi and compositions of small-degree mantle melts. Among other parameters, fO2 affects the water storage capacity and rheology of the mantle. The uppermost mantle, as represented by samples and partial melts, is sufficiently oxidized to sustain volatiles, such as H2O and CO2, as well as carbonatitic melts, but it is not known whether the shallow mantle is representative of the entire upper mantle. Using high-pressure experiments, we show here that large parts of the asthenosphere are likely to be metal-saturated. We found that pyroxene and garnet synthesized at >7 GPa in equilibrium with metallic Fe can incorporate sufficient ferric iron that the mantle at >250 km depth is so reduced that an (Fe,Ni)-metal phase may be stable. Our results indicate that the oxidized nature of the upper mantle can no longer be regarded as being representative for the Earth’s upper mantle as a whole and instead that oxidation is a shallow phenomenon restricted to an upper veneer only about 250 km in thickness. [ABSTRACT FROM AUTHOR]

Tritiated uracil and uridine have been prepared simultaneously from a mixture of their respective halogenated analogues (5-bromouracil and5-bromouridine) by halogen-tritium exchange in a one pot preparation, followed by purification. The tritiated products thus obtained have specific activities of 0.962 TBq/mmol and 1.036 TBq/mmol, respectively. [ABSTRACT FROM AUTHOR]

We discuss two methods that, through a combination of cyclically gluing copies of a given n-party boundary state in AdS/CFT and a canonical purification, creates a bulk geometry that contains a boundary homologous minimal surface with area equal to 2 or 4 times the n-party entanglement wedge cross-section, depending on the parity of the party number and choice of method. The areas of the minimal surfaces are each dual to entanglement entropies that we define to be candidates for the n-party reflected entropy. In the context of AdS3/CFT2, we provide a boundary interpretation of our construction as a multiboundary wormhole, and conjecture that this interpretation generalizes to higher dimensions. [ABSTRACT FROM AUTHOR]